Is blood cancer hereditary?
Cancers in the blood cells, bone marrow (where blood cells are made), or lymphatic system are together called blood cancers. Leukemia, lymfoma, and myeloma are all types of blood cancers and differ in their cell type of origin. In this post we’ll only briefly describe the various blood cancers – the focus will be on what is known about their heredity. You can read more about blood cancers in general at hematology.org.
Leukemia is a type of cancer that arises in the white blood cells (leukocytes). White blood cells are a part of our immune system and help the body defend itself against bacteria and viruses.
Leukemia is classified as acute or chronic depending on which lifecycle stage the white blood cell was in when it became cancerous. Acute lymphocytic leukemia (ALL) and acute myelogenous leukemia (AML) are acute leukemias. Chronic lymphocytic leukemia (CLL) and chronic myelogenous leukemia (CML) are chronic leukemias. CLL and AML are the most common leukemias, with 550 new cases of CLL and 300 new cases of AML each year in Sweden. CML and ALL are less common, with 100 and 50 new cases per year in Sweden, respectively.
Is leukemia hereditary?
The vast majority of leukemias are not hereditary and are caused by other factors. More recently, however, it has been understood that heredity can sometimes play a role in leukemia. Close relatives of someone with leukemia can have an increased risk of developing leukemia themselves. Given that leukemia is rare, the risk of developing leukemia, even for those with increased risk, is generally quite low. For this reason, a hereditary cancer assessment is only recommended for certain types of leukemia. Heredity and/or early detection can help inform treatment for certain types of leukemia, while for others it does not.
Li Fraumeni syndrome, caused by a pathogenic variant in the gene TP53, increases risk of ALL. Other rare syndromes or hereditary conditions can also increase risk of ALL or AML. ALL or AML can even be hereditary in the absence of a diagnosed syndrome or condition, and present as an accumulation of leukemia in the family.
The criteria for suspected heredity and assessment vary. Hereditary ALL in the absence of an underlying genetic syndrome is suspected when there are two or more close relatives who have been diagnosed with ALL, AML, or myelodysplastic syndrome (MDS). Hereditary AML is suspected when there are two or more close relatives who have been diagnosed with AML, MDS, or thrombocytopenia. For both ALL and AML, one relative must have been diagnosed before age 50 if there are not more than two relatives with one of these cancers. More detailed guidelines can be found in the clinical guidelines for ALL and AML.
An accumulation of CLL is seen in roughly 5% of families with CLL. In these families, a close relative of someone with CLL has a somewhat increased risk of developing the same. The same patterns have not been seen for CML, indicating that hereditary factors do not play a significant role in CML development.
Lymphoma is a type of cancer that arises in in the lymphatic system. This system produces immune cells to defend the body against bacteria and viruses. The many kinds of lymphoma are categorized as Hodgkins lymphoma, non-Hodgkins lymphoma, or T-cell lympoma. In Sweden, roughly 2500 people are diagnosed with Lymphoma each year.
Is lymphoma hereditary?
An accumlation of lymphoma can occur in some families, indicating an increased risk for close relatives. The biggest risk in this case is to develop the same kind of lymphoma, but there also lies a risk of developing a different kind of lymphoma. The overall risk of developing lymphoma, with or without hereditary risk, is too low to motivate screening.
Myeloma is a type of cancer that arises in plasma cells, a type of white blood cell primarily found in the bone marrow. Roughly 660 people are diagnosed with myeloma in Sweden each year.
Is myeloma hereditary?
Heredity plays only a very small role in the development of myeloma. But just as with the other blood cancers, an accumulation of myeloma in a family indicates an increased risk for close relatives. No screening programs exist today, as the risk, even when increased, is extremely low.
Should you do a hereditary cancer assessment if there is blood cancer in your family?
As previously mentioned, families who meet certain criteria should get assessed for hereditary risk of acute leukemia. Which genes are tested is determined based on the family’s cancer history and any symptoms that may be linked to a particular syndrome. For example, analysis of the TP53 gene is relevant for a family with leukemia in combination with early breast cancer, sarcoma, and/or a brain tumor. GeneMate® includes analysis of many of the genes related to specific cancer syndromes that are known to cause blood cancer. We welcome you to contact us with any questions regarding whether testing may be relevant for your family.